Keyboard from 2010 built by TG3 for a Siemens chemistry analyzer. I cleaned it up, added some weight to the bottom, and converted to USB. Cherry MX Black and PBT Dye-subbed DCS caps. Take a peek at what should be F9 and F10 (and are after conversion), as well as some of the keys above the numpad, which, tangentially, now has 5 keys that do absolutely nothing related to what's written on them.
I prefer RP2040 stuff when I make a keyboard, but (most) Pro Micros use 5v I/O, while the RP2040 uses 3.3V. XT/AT keyboards also run at 5V. That means it's generally just easier on these conversions to stick with the tried and true, and people have managed to cram VIAL builds onto the memory footprint, which makes it even better.
I'm only had to do this sort of thing with my Model F XTs (my AT works with a standard passive AT->ps/2 adapter->usb adapter). RP2040s weren't even a thing when I was playing with this stuff, but I don't doubt there are some great QoL improvements.